DE102015202179B4 - Method and device for determining hand rigidity - Google Patents

Abstract

A method for determining a stiffness of the human hand (7, 70, 700), wherein at least one muscle signal of an intrinsic hand muscle is detected and from it a stiffness of a human hand is determined.

Description

The present invention relates to a method and a device for determining a stiffness of a human hand by detecting a muscle signal of an intrinsic hand muscle, in particular for use in devices for teleoperation, robots or prostheses and a system of a device for determining a stiffness of a human hand and a Apparatus for teleoperation, a robot or a prosthesis.

It is known from the state of the art, Grebenstein, Markus et al., "The DLR Hand Arm System", ICRA 2011, May 9-13, 2011, Shanghai, China, that novel robotic systems have the possibility of a compliance adjustment and an external one can yield accordingly attacking force. The compliance can be active or passive. For active compliance, a control based on a force or torque measurement can be used. In passive compliance, an implemented mechanical spring or damper may be provided. Both the active and the passive compliance can be adjusted in their parameters, such as via a so-called antagonistic mechanism similar to humans. This means that it can respond to different amounts or nature of forces of different kinds. This can be done for example by adjusting the spring stiffness or the setting of damping parameters. This adaptation was modeled on humans. Man has both the possibility of active, for example, reflex, and passive, passive properties of the muscle parameter, adjustment of compliance. This adaptation allows him to optimally adapt the rigidity parameters of his musculoskeletal system, such as arms, legs and fingers, for different tasks with different demands on speed and accuracy.

From Shin D. Kim J, Koike Y (2009) "A myokinetic arm model for estimating joint torque and stiffness from EMG signals during maintained posture", Journal of Neurophysiology 101; 387-401 shows a teleoperation with impedance parameters from the detection of muscle activities of the human arm.

Other studies are concerned with the teleoperation of finger forces from measuring muscle activity in the forearm, preferably for teleoperation of forces of a hand amputee to control an active hand prosthesis.

The prior art does not allow the explicit teleoperation of mechanical impedance parameters of the human hand, it is limited to the arm. Furthermore, the prior art in the teleoperation of finger forces is limited exclusively to the detection of the muscle signals in the forearm, the so-called extrinsic hand muscles. The major drawback here is that the forearm muscle signals correlate strongly with forearm rotation (one degree of freedom) and wrist movement (two degrees of freedom). The muscles under the skin move during a forearm rotation so that in two different positions of the forearm, the signals of different muscles are detected when using electromyographic surface electrodes. Therefore, it is known in the literature that to acquire the finger forces from the muscle activity of this muscle group, it is always necessary to calibrate this new one for each person and also when the electrodes are newly applied in order to obtain a force from the muscle signal.

Other disadvantages of the prior art require the introduction of permanent mechanical disturbances, so-called perturbations, such as shifts and the simultaneous detection of the reactions by means of sensors, for example force sensors, for the continuous measurement of the impedance. These measurements often also contain the response of the reflexes. A permanent mechanical disturbance for measuring the impedance is very hindering in a teleoperation task, where particularly high precision is required, and thus limits the possibility of this.

Out DE 10 2010 052 430 B4 For example, a method is known in which a gripping force is measured in an interface to a robot. In addition to the force measurement done, the muscle length is estimated based on the measurement of muscle activity. From the measurement of the gripping force and the estimation of the muscle length, an estimation of the stiffness of the human being takes place.

The aim is therefore to determine these stiffness parameters in humans in an improved manner and to transfer them to a device for teleoperation, a robotic system or a prosthesis. In addition, the measurements should be as trouble-free and continuous as possible.

This object is achieved with a method for determining a stiffness of a human hand with the features of claim 1, a device for determining a stiffness of a human hand with the features of claim 8, and a system of a device for determining a stiffness of a human hand and a device for teleoperation, a robot or a prosthesis with the features of Claim 14 solved. Advantageous further embodiments are given in each of the subclaims. All combinations, as well as only individual combinations between the method, the device and the system can be used together. Furthermore, it is also provided in each case as possible to combine individual or even several features of the method, the device or the system as desired.

According to the invention, a method for determining a stiffness of the human hand is proposed, wherein at least one muscle signal of an intrinsic hand muscle is detected and from this a rigidity of a human hand is determined.

• • Erfassen eines Muskelsignals eines intrinsischen Handmuskels,
• • Übertragung des Muskelsignals an eine Einheit zur Datenverarbeitung und
• • Bestimmung der Steifigkeit einer menschlichen Hand aus dem Muskelsignal mittels der Einheit zur Datenverarbeitung

aus.In a further embodiment, the method is characterized by the method steps

• Detecting a muscle signal of an intrinsic hand muscle,
• • transmission of the muscle signal to a data processing unit and
• • Determining the stiffness of a human hand from the muscle signal by means of the data processing unit

out.

A prosthesis can be designed as an active hand or partial hand prosthesis.

From the measurements of finger stiffnesses and the simultaneous signal acquisition of the intrinsic, hand-held, and extrinsic, forearmed, hand muscle activity, it has surprisingly been found that much of the recorded variability of finger stiffness during the use of co-contractions of the muscles, simultaneous Tensioning of antagonistic muscle pairs, which explains the discovered variability in intrinsic muscle activity.

Furthermore, it has been found that by measuring the muscle signals to persons sufficiently accurate statements from these muscle signals on stiffness and force can be closed to unknown subjects. This means that the found variability of the intrinsic muscles is particularly low. Among other things, the intrinsic muscles change their position only slightly compared to extrinsic muscles with a wrist movement or a forearm rotation.

Intrinsic muscles include, in particular, the muscles in the hand, such as the interosseous dorsal muscles I-IV, the interosseous palmar muscles I-III, the thenar muscles (abductor pollicis brevis, adductor pollicis, flexor pollicis brevis, opponens pollicis). , the muscles of the hypothenar (Mm. abductor digiti minimi, flexor digiti mimini, opponens digiti minimi), as well as the muscles palmaris brevis.

The muscle signals of the intrinsic hand muscles are therefore related to the hand stiffness. As a hand in this context also the fingers are to be understood as involved.

A muscle signal is an electromyographic signal, which results from the change in potential at the muscle surface. Upon excitation of a muscle cell, a potential change can be measured, which can be detected by electrodes attached to the skin. Such electrodes are referred to in this context as electromyographic electrodes, short EMG electrodes.

In a further embodiment of the method, the rigidity is transferred to a device for teleoperation, to a robot or to a prosthesis, preferably a hand prosthesis and particularly preferably an active hand prosthesis.

For example, the human hand is coupled to an input side which detects signals from intrinsic hand muscles. A robot or a device for teleoperation and a prosthesis can represent an output page. From the measured signals stiffness of the human hand are determined and then transferred to the kinematics of the output side. The output side can be a partial hand prosthesis.

In another example, signals from a human hand may be picked up and transmitted to a teleoperation system remote from humans, for example, to perform work in places hard to reach by humans.

Another field of application is, for example, a robot to which measured muscle signals are transmitted. Furthermore, it is possible that such signals are stored and retrieved by the robot as needed to execute routines.

Another area of application is, for example, virtual reality or computer games.

In another example, a visual and / or a tactile force feedback of the output side may be transmitted to the input side.

In a further embodiment of the method, a muscle and / or a position of the muscle signal in addition to or separately from a stiffness of a human hand Hand or at least one finger of the hand to be determined. In this context, all combinations are possible. It can also be provided, for example, that the rigidity represents a grip stiffness of the hand or a finger rigidity.

In a further embodiment of the method, the muscle signal is detected via at least one electrode, preferably an electromyographic electrode, in short EMG electrode.

The surface electrodes may be monopolar, differential (bipolar) or multi-differential. For example, MYOBOCK electrodes from ottobock, Delsy's Trigno Wireless System or the NIHON KOHDEN H851 pure silver surface electrode set can be used.

According to a further aspect of the invention, in addition to or separately therefrom, there is provided a device for determining a stiffness of a human hand having at least one electrode arranged on the hand and the electrode for detecting muscle signals of intrinsic muscles and having a data processing unit proposed for determining a rigidity of a human hand by means of a measurement signal detected by the electrode.

The measurement signal detected by the electrode is preferably a muscle signal of an intrinsic hand muscle.

The electrode is preferably designed as an electromyographic electrode. Furthermore, the electrode can be integrated into a glove, preferably sewn or glued into the glove.

In a further embodiment, a connection for signal transmission between the electrode and the unit for data transmission is provided. This connection for signal transmission can be designed both as a direct connection, for example by a cable or a line or as an indirect connection, such as a wireless connection, such as wireless connection or Bluetooth.

In a further embodiment of the device, force moment sensors, for example in the area of the fingertips, can be provided. Furthermore, position sensors, for example on the fingers, may also be provided. These position sensors can be designed as strain gauges.

Furthermore, the finger force or finger position can also be determined from the evaluation of the detected muscle signals of the intrinsic hand muscles with the device.

In a further embodiment, a plurality of electrodes for detecting a muscle signal may be provided.

The electrodes are preferably arranged on the skin surface. Particularly preferably, the electrodes are attached to the skin surface directly above the muscles whose muscle signals are to be detected. The electromyographic electrodes are integrated, for example, in a glove with or without fingers, which also allows precise repositioning of the electrodes on different intrinsic muscles. The glove can be designed in different sizes of hand to ensure adaptation to different sized hands, such as a female or male hand. The glove may additionally include sensors for precise detection of finger positions and forces. For this example, strain gauges may be provided, as they are known in the art from so-called cyber gloves. Such position sensors can detect the joint position of the thumb and fingers. Furthermore, additional force sensors can be arranged, for example, in the region of the fingertips, which detect a force when gripping on each phalanx of the fingers in up to six degrees of freedom. The transmission of the measured data, the muscle signals, the finger positions and forces can be done by means of a cable or wirelessly. The measured signals are forwarded to a data processing unit, for example a corresponding computer system for data evaluation or a chip.

In a further embodiment, a pre-evaluation of muscle and finger position or finger force signals, for example on a circuit board or a chip, take place, which can also be mounted on the glove.

In a further embodiment, a battery can also be integrated in the glove, which allows a free movement independent of cables or a connection to a power supply.

According to a further aspect of the invention, in addition to or separately therefrom, there is proposed a system consisting of a device for determining a stiffness of a human hand as described above and a device for teleoperation, a robot or a prosthesis, whereby the method according to the above description is carried out.

Further advantageous embodiments and further developments are specified in the following figures. However, the resulting respective features are not limited to individual figures or embodiments. Rather, one or more features of the above description may be combined with single or multiple features of the figures in addition to further developments.

Show it:

1 a first embodiment of a device for determining a stiffness of a human hand,

2 an embodiment of a system of a device for determining a stiffness of a human hand and a prosthesis and

3 a further embodiment of a device for determining a stiffness of a human hand.

Out 1 goes a device 1 for determining a stiffness of a human hand 7 out. The device 1 includes a unit for data evaluation 2 which about connections 6 with electrodes 3 communicate. The unit for data processing 2 and the electrodes 3 are in a glove 5 integrated.

2 makes a system out of a device 10 for determining a stiffness of a human hand 70 and a prosthesis 40 This system is suitable, for example, for the replacement of partial hand loss. The illustrated human hand 70 in the view of palmar the thumb is missing, which by an active robotic prosthesis 40 is replaced. By such a prosthesis 40 in combination with a device 10 for determining a stiffness of a human hand 70 there is the possibility of adjustability of the denture stiffness. In addition, the muscle signals of the remaining intrinsic muscles in the hand 70 by means of arranged on the hand surface electromyographic electrodes 30 recorded and from it with the unit for data processing 20 determines the necessary compliance or stiffness of the thumb. A connection to the signal transmission, the rigidity to the control unit 90 the prosthesis 40 transfer. The control unit 90 controls with this data the movement of the thumb.

The electrodes are placed directly on the skin and in a glove 50 integrated. The muscle signals arising during muscle activity of the intrinsic muscles are transmitted through the electrodes 30 detected and via connections for signal transmission 60 to the unit for data processing 20 pass on. This control unit 90 is via a connection for signal transmission 80 connected to the unit for data processing, so that the unit for data processing 20 as an input side, and the control unit of the prosthesis functions as an output side.

3 represents a further embodiment of a device 100 for determining a stiffness of a human hand 700 It is a right hand 700 shown in a palmar view. About the hand 700 is a glove 500 pulled in the electromyographic electrodes 300 are integrated. Furthermore, this device has 100 additional force and moment sensors 800 in the area of the fingertips. The electromyographic electrodes 300 lie on the skin. Other electromyographic electrodes are located on the dorsal side of the glove shown in a similar arrangement. Furthermore, this embodiment comprises position sensors 900 on the finger sides. With the position sensors 900 and the force and moment sensors 800 In addition, all joint positions of the fingers and the force and torque action can be detected in a total of six degrees of freedom at each distal phalanx of the fingers. With the illustrated glove it is possible to detect positional forces and torques, as well as mechanical impedance properties of the hand and to transmit this to a robotic system or a robotic hand. In this embodiment, a data processing unit 200 shown outside the glove. This is via a wireless connection 600 connected to the electrodes, so that of the sensors 800 . 900 and electrodes 300 detected signals over the wireless connection 600 to the unit for data processing 200 be transmitted. The unit for data processing 200 determined from these signals at least one hand stiffness.

Claims (14)

Method for determining the rigidity of the human hand ( 7 . 70 . 700 ), wherein at least one muscle signal of an intrinsic hand muscle is detected and from this a stiffness of a human hand is determined. Method according to Claim 1, characterized by the following method steps: detection of a muscle signal of an intrinsic hand muscle, transmission of the muscle signal to a data processing unit ( 2 . 20 . 200 ) and determination of the stiffness of a human hand ( 7 . 70 . 700 ) from the muscle signal by means of the data processing unit ( 2 . 20 . 200 ). Method according to one of claims 1 or 2, characterized in that the rigidity of a device for teleoperation, on a robot or a prosthesis ( 40 ), is transmitted. Method according to one of claims 1 to 3, characterized in that from the muscle signal additionally or separately from a stiffness of a human hand ( 7 . 70 . 700 ) a force and / or position of a hand ( 7 . 70 . 700 ) or at least one finger of the hand ( 7 . 70 . 700 ) is determined. Method according to one of claims 1 to 4, characterized in that the rigidity of a hand grip ( 7 . 70 . 700 ) or a finger stiffness. Method according to one of claims 1 to 5, characterized in that the muscle signal via at least one electrode ( 3 . 30 . 300 ) is detected. Method according to claim 6, characterized in that the electrode ( 3 . 30 . 300 ) is an electromyographic electrode. Device for determining rigidity ( 1 . 10 . 100 ) of a human hand ( 7 . 70 . 700 ), with at least one electrode ( 3 . 30 . 300 ), which are at hand ( 7 . 70 . 700 ) and wherein the electrode ( 3 . 30 . 300 ) is set up to acquire muscle signals from intrinsic hand muscles and is equipped with a data processing unit ( 2 . 20 . 200 ) used to determine the rigidity of a human hand ( 7 . 70 . 700 ) by means of one of the electrode ( 3 . 30 . 300 ) detected muscle signal is established. Contraption ( 1 . 10 . 100 ) according to claim 8, characterized in that the electrode ( 3 . 30 . 300 ) is designed as an electromyographic electrode. Contraption ( 1 . 10 . 100 ) according to claim 8 or 9, characterized in that the electrode ( 3 . 30 . 300 ) in a glove ( 5 . 50 . 500 ) is integrated. Contraption ( 1 . 10 . 100 ) according to claim 10, characterized in that the electrode ( 3 . 30 . 300 ) in the glove ( 5 . 50 . 500 ) is sewn or glued. Contraption ( 1 . 10 . 100 ) according to one of claims 8 to 11, characterized by at least one connection for signal transmission ( 6 . 60 . 600 ) between the electrode ( 3 . 30 . 300 ) and the data processing unit ( 2 . 20 . 200 ). Contraption ( 1 . 10 . 100 ) according to claim 12, characterized in that the connection for signal transmission ( 6 . 60 . 600 ) is executed as a direct or indirect connection. System consisting of a device for determining rigidity ( 1 . 10 . 100 ) of a human hand according to one of claims 8 to 13 and a device for teleoperation, a robot or a prosthesis ( 40 ), characterized by, means for carrying out the method according to one of claims 3 to 7.

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